A 23-year-old man with a history of Legg-Perthes' disease of the left hip was evaluated with Tc-99m MDP bone scan for left hip pain following a recent fall. Slight increased activity was shown in the left hip when compared with the right hip. This was thought to correspond with radiographically demonstrated degenerative changes of the left hip. Unexpected intense radionuclide activity was demonstrated in the thyroid gland, as was pertinent absence of relative increased activity in the stomach and salivary glands. Follow-up thyroid scan and RAI uptake demonstrated diffuse toxic goiter, which was subsequently treated with I-131.